Influence of the cation in hypophosphite-mediated catalyst-free reductive amination

• Natalia Lebedeva,
• Fedor Kliuev,
• Olesya Zvereva,
• Klim Biriukov,
• Evgeniya Podyacheva,
• Maria Godovikova,
• Oleg I. Afanasyev and
• Denis Chusov

Beilstein J. Org. Chem. 2025, 21, 1661–1670, doi:10.3762/bjoc.21.130

• to fundamentally study the influence of the cations in hypophosphites on this process. In this work, the hypophosphites of Li, K, Rb, and Cs were obtained in situ, the influence of alkali metal cations on the efficiency of reductive amination was assessed and the obtained results were compared with

• investigation of cation influence on the efficiency of reductive amination, a commercially available NaH2PO2, and in situ synthesized LiH2PO2, NaH2PO2, KH2PO2, RbH2PO2, and CsH2PO2 were compared. To account for the reactivity of H3PO2 as is, the reaction outcome both for the neutral XH2PO2 (where X is Li, Na, K

• additional H3PO2 showed lower efficiency at 130 °C, 4 h (3–55%) (Table 1, lines 4–6). However, the reactivity of the mixture of XH2PO2 and H3PO2 (at the same total H2PO2− loading) demonstrated an increased reaction yield. K2CO3 was cheaper and more available base than RbOH and Cs2CO3, hence it was chosen for

On the aromaticity and photophysics of 1-arylbenzo[a]imidazo[5,1,2-cd]indolizines as bicolor fluorescent molecules for barium tagging in the study of double-beta decay of ¹³⁶Xe

• Eric Iván Velazco-Cabral,
• Fernando Auria-Luna,
• Juan Molina-Canteras,
• Miguel A. Vázquez,
• Iván Rivilla and
• Fernando P. Cossío

Beilstein J. Org. Chem. 2025, 21, 1627–1638, doi:10.3762/bjoc.21.126

• efficiency of crown ethers as components in cation-selective fluorescent probes has been extensively explored [7][30], to the best of our knowledge no previous computational DFT studies on the selectivity of crown ethers of different sizes with Ba2+ have been reported. Therefore, we explored (Scheme 2A) the

Synthesis of optically active folded cyclic dimers and trimers

• Ena Kumamoto,
• Kana Ogawa,
• Kazunori Okamoto and
• Yasuhiro Morisaki

Beilstein J. Org. Chem. 2025, 21, 1603–1612, doi:10.3762/bjoc.21.124

• luminescence (CPL) [22][23][24][25] with high photoluminescence (PL) quantum efficiency (ΦPL) and anisotropy. Additionally, the π-stacked structure of [2.2]paracyclophane can be applied at a crossing point. By folding the π-conjugated system using [2.2]paracyclophane as the chiral crossing unit, optically

• samples were analyzed in CHCl3 at room temperature. Photoluminescence (PL) spectra were recorded on a JASCO FP-8500 spectrofluorometer, and samples were analyzed in CHCl3 at room temperature. Absolute PL quantum efficiency was calculated on a JASCO FP-8500 with an ILF-835 integrating sphere. The PL

3-Aryl-2H-azirines as annulation reagents in the Ni(II)-catalyzed synthesis of 1H-benzo[4,5]thieno[3,2-b]pyrroles

• Julia I. Pavlenko,
• Pavel A. Sakharov,
• Anastasiya V. Agafonova,
• Derenik A. Isadzhanyan,
• Alexander F. Khlebnikov and
• Mikhail S. Novikov

Beilstein J. Org. Chem. 2025, 21, 1595–1602, doi:10.3762/bjoc.21.123

• an ortho-substituent into the benzene ring also has no effect on the synthesis efficiency (compound 3f). A slight decrease in yield was observed only for the naphthyl-substituted annulation product 3k. The plausible mechanism of the reaction involves the nucleophilic addition of the Ni-enolate of 1

• ). Benzothienopyrrole 3b was methylated using the MeI/NaH system into 1-methyl-substituted derivative 6 in 81% yield. With the same efficiency, when compound 3b was treated with di-tert-butyl dicarbonate in the presence of 4-(dimethylamino)pyridine (DMAP), Boc-derivative 7 was obtained. Finally, the formylation of 3b

Facile synthesis of hydantoin/1,2,4-oxadiazoline spiro-compounds via 1,3-dipolar cycloaddition of nitrile oxides to 5-iminohydantoins

• Juliana V. Petrova,
• Varvara T. Tkachenko,
• Victor A. Tafeenko,
• Anna S. Pestretsova,
• Vadim S. Pokrovsky,
• Maxim E. Kukushkin and
• Elena K. Beloglazkina

Beilstein J. Org. Chem. 2025, 21, 1552–1560, doi:10.3762/bjoc.21.118

• -oxadiazoline spiro-compounds using a 1,3-dipolar cycloaddition of nitrile oxides to C=N bonds of 5-iminohydantoins. The efficiency of the approach was demonstrated by varying the substituents at four positions of the resulting spirocyclic molecules. Cytotoxicity of the target hydantoin/1,2,4-oxadiazolines was

Azide–alkyne cycloaddition (click) reaction in biomass-derived solvent Cyrene^TM under one-pot conditions

• Zoltán Medgyesi and
• László T. Mika

Beilstein J. Org. Chem. 2025, 21, 1544–1551, doi:10.3762/bjoc.21.117

• obtained for Cu sources in different solvent systems [40][41]. Although CuAAC reactions can be efficiently performed in water, the moisture content of the organic reaction environment could have a significant effect on the efficiency of a transition-metal-catalyzed reaction. Because CyreneTM is fully

• formation; thus, keeping water content below 1% is necessary to maintain high reaction efficiency. The negative effect could be due to the decreased solubility of 2a at higher water content [42][43][44]. Hereafter, the readily available CuI was selected as a catalyst precursor to facilitate click reactions

General method for the synthesis of enaminones via photocatalysis

• Paula Pérez-Ramos,
• Raquel G. Soengas and
• Humberto Rodríguez-Solla

Beilstein J. Org. Chem. 2025, 21, 1535–1543, doi:10.3762/bjoc.21.116

• phenantroline also resulted in a decrease in the efficiency of the process (Table 1, entries 4 and 5). The pyridinium salt has also a significant effect on reactivity; thus, when 1-benzyl-2,4,6-triphenylpyridin-1-ium (PS2) was used, enaminone 9a was isolated in only 34% yield (Table 1, entry 6). Replacing DMF

Calcium waste as a catalyst in the transesterification for demanding esters: scalability perspective

• Anton N. Potorochenko and
• Konstantin S. Rodygin

Beilstein J. Org. Chem. 2025, 21, 1520–1527, doi:10.3762/bjoc.21.114

• the alcohols’ nature and catalyst amount (1–10 wt %). The CS600 catalyst demonstrated efficiency in the transesterification of low-molecular-weight esters, medium-chain triglycerides (C9–C12), and lactones, resulting in the corresponding methyl esters in 66–99% yields in the presence of low catalyst

Highly distinguishable isomeric states of a tripodal arylazopyrazole derivative on graphite through electron/hole-induced switching at ambient conditions

• Himani Malik,
• Sudha Devi,
• Debapriya Gupta,
• Ankit Kumar Gaur,
• Sugumar Venkataramani and
• Thiruvancheril G. Gopakumar

Beilstein J. Org. Chem. 2025, 21, 1496–1507, doi:10.3762/bjoc.21.112

• electronic and optical properties of switchable states. The applicability of molecular switches relies on the efficiency, reversibility, and the half-life associated with different non-equilibrium states. Typically, the half-life of the Z isomer of AB is a few days [17]. Chemical modifications of AB

• switchable probe for light-driven reversible printing and erasing applications [29]. Besides exhibiting excellent photoswitching in solution phase, the tripodal photoswitches exhibit extended half-life of the ZZZ isomer in the solid-state as well [22][29]. The overall efficiency of the molecular switch could

• surface at ambient conditions. The fluorine substitution is chosen in FNAAP for its better photoisomerization efficiency (in solution as well as in solid state) and higher molecular stability [29]. Possible photoisomers of FNAAP, EEE, EEZ, EZZ and ZZZ are shown in Figure 1. FNAAP molecules assemble into

Photoredox-catalyzed arylation of isonitriles by diaryliodonium salts towards benzamides

• Nadezhda M. Metalnikova,
• Nikita S. Antonkin,
• Tuan K. Nguyen,
• Natalia S. Soldatova,
• Alexander V. Nyuchev,
• Mikhail A. Kinzhalov and
• Pavel S. Postnikov

Beilstein J. Org. Chem. 2025, 21, 1480–1488, doi:10.3762/bjoc.21.110

• . Unfortunately, 4CzTPN, 4CzIPN, and 3DPAFIPN did not demonstrate increased efficiency, and the yields of the target product 2aa were slightly lower than for [Ru(bpy)3](PF6)2 (Table 1, entries 4–6). Thus, all further optimization studies were done using [Ru(bpy)3](PF6)2 as a catalyst. After, we moved to the

Microwave-enhanced additive-free C–H amination of benzoxazoles catalysed by supported copper

• Andrei Paraschiv,
• Valentina Maruzzo,
• Filippo Pettazzi,
• Stefano Magliocco,
• Paolo Inaudi,
• Daria Brambilla,
• Gloria Berlier,
• Giancarlo Cravotto and
• Katia Martina

Beilstein J. Org. Chem. 2025, 21, 1462–1476, doi:10.3762/bjoc.21.108

• ][44] and sulfamoyl chlorides [32] can perform the coupling under basic conditions, the need for the activation of the amine as an electrophilic agent generates additional waste. This reduces atom economy and indicates lower reaction efficiency. Acid-catalysed protocols have also been specifically

• . Additionally, using supported metals instead of metal salts can prevent the formation of chelates, which might otherwise impact the efficiency of the procedure. Moreover, this approach can provide bifunctional catalysis as the support itself contributes to the catalyst's reactivity, thus enhancing its overall

• efficiency. In the context of the C2 amination of azoles, to the best of our knowledge, only a few studies [48][50] have explored this approach, suggesting significant opportunities for further development and improvement. Building on our previous experience in the preparation and characterisation of

Advances in nitrogen-containing helicenes: synthesis, chiroptical properties, and optoelectronic applications

• Meng Qiu,
• Jing Du,
• Nai-Te Yao,
• Xin-Yue Wang and
• Han-Yuan Gong

Beilstein J. Org. Chem. 2025, 21, 1422–1453, doi:10.3762/bjoc.21.106

• (FWHM = 36 nm), |glum| = 1.1 × 10−3, |gEL| = 1.5 × 10−3, and an external quantum efficiency (EQE) of 0.14 – demonstrating promise for CPL-OLED applications [22]. Wanichacheva’s team reported urazole-functionalized aza[5]helicene 10, exhibiting selective Fe(III) sensing, marked solvatochromism, and a

• for high-efficiency chiral optoelectronic and quantum materials. In 2024, Kivala’s group selectively synthesized highly distorted [6]helicenes 29a and 29b incorporating azocine units via a regioselective Beckmann rearrangement from oxime precursor 29c [43] (Table 8). For comparative evaluation, the

• autoclave, achieving a 44% yield [51] (Table 12). In a 1 wt % PMMA-dispersed film, compound 37 exhibited ultra-narrowband emission (FWHM = 16 nm) at 484 nm with an 80% PLQY. OLEDs based on 37 demonstrated excellent external quantum efficiency, current efficiency, and power efficiency. Duan and co-workers

Tautomerism and switching in 7-hydroxy-8-(azophenyl)quinoline and similar compounds

• Lidia Zaharieva,
• Vera Deneva,
• Fadhil S. Kamounah,
• Nikolay Vassilev,
• Ivan Angelov,
• Michael Pittelkow and
• Liudmil Antonov

Beilstein J. Org. Chem. 2025, 21, 1404–1421, doi:10.3762/bjoc.21.105

• E/Z isomerization around the C=N bond leads to reduced efficiency of the tautomeric based switching [52]. In this respect, based on the excellent stability of the azo compounds, it is interesting to understand the effect of the competitive proton transfer and E/Z switching by replacement of the

• part is flexible, the excitation of E can lead to E/Z isomerization, which competes with the initial excited-state PT process, reducing its efficiency [52]. The theoretical data, collected in Table 1, can shed light on the potential energy landscape in the ground state for the studied compounds

High-pressure activation for the solvent- and catalyst-free syntheses of heterocycles, pharmaceuticals and esters

• Kelsey Plasse,
• Valerie Wright,
• Guoshu Xie,
• R. Bernadett Vlocskó,
• Alexander Lazarev and
• Béla Török

Beilstein J. Org. Chem. 2025, 21, 1374–1387, doi:10.3762/bjoc.21.102

• generation. Using water as pressure transmitting fluid, the reaction vessel is immersed in water minimizing fire hazard during the reactions. Finally, most procedures can be carried out at ambient temperature, improving safety and energy efficiency. Energy efficiency is also supported by the nature of the

Oxetanes: formation, reactivity and total syntheses of natural products

• Peter Gabko,
• Martin Kalník and
• Maroš Bella

Beilstein J. Org. Chem. 2025, 21, 1324–1373, doi:10.3762/bjoc.21.101

• transfer. In the second protocol, the β-lactone intermediates 7 are reduced to a diol and a subsequent Williamson etherification affords the oxetanes. Since both protocols consist of two steps and give only moderate yields, the overall oxetane yield and synthetic efficiency are rather low. In 2019, Marini

Recent advances in amidyl radical-mediated photocatalytic direct intermolecular hydrogen atom transfer

• Hao-Sen Wang,
• Lin Li,
• Xin Chen,
• Jian-Li Wu,
• Kai Sun,
• Xiao-Lan Chen,
• Ling-Bo Qu and
• Bing Yu

Beilstein J. Org. Chem. 2025, 21, 1306–1323, doi:10.3762/bjoc.21.100

• transfer (HAT) in photocatalytic reactions. These radicals display exceptional selectivity and efficiency in abstracting hydrogen atoms from C–H, Si–H, B–H, and Ge–H, positioning them as invaluable tools in synthetic chemistry. This review summarizes the latest advancements in the photocatalyzed generation

• prefunctionalization through directing group (DG) incorporation, inevitably necessitating covalent DG-metal coordinative anchoring. This prerequisite fundamentally compromises both atomic efficiency and synthetic practicality, thereby imposing fundamental constraints on the catalytic system's intrinsic sustainability

• /mol (Figure 2a) [28][29][30]. Almost 5 kcal/mol difference between two species could spontaneously undergo a HAT process. That also justifies the selectivity and efficiency of amidyl radical serving as HAT reagent. 2) Recent research indicated a critical correlation between electronic effects and

Recent advances in oxidative radical difunctionalization of N-arylacrylamides enabled by carbon radical reagents

• Jiangfei Chen,
• Yi-Lin Qu,
• Ming Yuan,
• Xiang-Mei Wu,
• Heng-Pei Jiang,
• Ying Fu and
• Shengrong Guo

Beilstein J. Org. Chem. 2025, 21, 1207–1271, doi:10.3762/bjoc.21.98

• groups on the aromatic ring (40a–d), effectively underwent this transformation. Halogen substituents (40e, 40f) on the substrates also demonstrated excellent reaction efficiency and substrate tolerance, further broadening the potential scope of applications. Regarding the reaction mechanism (Scheme 22

• . The results indicated that the N-protecting group had little impact on the reaction’s efficiency, and various substrates (e.g., methyl, benzyl, isopropyl) were effectively converted to their respective target products 50a–c. Moreover, benzene rings bearing different substituents, whether electron

• reagents, were tested, ranging from electron-donating to electron-withdrawing groups. These substrates consistently achieved moderate to excellent yields, demonstrating high reaction efficiency of the catalytic system under the standard conditions. The reaction mechanism was investigated through controlled

Synthesis of β-ketophosphonates through aerobic copper(II)-mediated phosphorylation of enol acetates

• Alexander S. Budnikov,
• Igor B. Krylov,
• Fedor K. Monin,
• Valentina M. Merkulova,
• Alexey I. Ilovaisky,
• Liu Yan,
• Bing Yu and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2025, 21, 1192–1200, doi:10.3762/bjoc.21.96

• efficiency, strong basic or acidic conditions, and excess of organohalides as starting materials. Recent years have witnessed the upsurge of free-radical oxidative phosphorylation transformations that became a reliable strategy for the construction of C–P bonds in organophosphorus chemistry [2][32][33][34

Enhancing chemical synthesis planning: automated quantum mechanics-based regioselectivity prediction for C–H activation with directing groups

• Julius Seumer,
• Nicolai Ree and
• Jan H. Jensen

Beilstein J. Org. Chem. 2025, 21, 1171–1182, doi:10.3762/bjoc.21.94

• the potential to significantly accelerate the discovery and optimization of new synthetic routes, thereby impacting materials science and medicinal chemistry by facilitating the synthesis of novel compounds with high precision and efficiency. Pattern Matching Tomberg et al. [9] assembled a look-up

A multicomponent reaction-initiated synthesis of imidazopyridine-fused isoquinolinones

• Ashutosh Nath,
• John Mark Awad and
• Wei Zhang

Beilstein J. Org. Chem. 2025, 21, 1161–1169, doi:10.3762/bjoc.21.92

• –Bienaymé (GBB); imidazopyridine; intramolecular Diels–Alder (IMDA); isoquinolinone; multicomponent reaction (MCR); re-aromatization; Introduction Multicomponent reactions (MCRs) have intrinsic green chemistry advantages of synthetic efficiency and operational simplicity. Performing post-condensational

• tested, AlCl₃ gave the best result, while CuCl, ZnCl2, PdCl2 and Sc(OTf)3 showed moderate conversions (30–55%), and InCl3 had the lowest efficiency. Without any Lewis acid we observed no conversion by LC–MS (Table 1, entry 16). During the reaction, IMDA adduct 7a was detected by LC–MS (Figure S1

Synthetic approach to borrelidin fragments: focus on key intermediates

• Yudhi Dwi Kurniawan,
• Zetryana Puteri Tachrim,
• Teni Ernawati,
• Faris Hermawan,
• Ima Nurasiyah and
• Muhammad Alfin Sulmantara

Beilstein J. Org. Chem. 2025, 21, 1135–1160, doi:10.3762/bjoc.21.91

• over 25 steps in 11% overall yield. On the other hand, the efficiency of the process was emphasized by the authors on the utilization of Roche esters 29 and ent-29 to prepare stereochemically pure sulfones 27 and ent-27, respectively. Moreover, the use of the trityl protecting group facilitated a

• stereocenter, significantly reducing overall efficiency. To overcome this challenge, Laschat’s approach leveraged a chiral pool building block – methyl-branched preen gland wax ester – as the starting material. This ester already contained three methyl groups pre-installed with the stereochemistry necessary

• and deprotection steps, functional group transformations, stereocontrolled allylation, cross-metathesis, and Horner–Wadsworth–Emmons (HWE) olefination. This method highlights the power of catalytic stereocontrol, achieving the complex architecture of borrelidin fragments with efficiency and precision

Gold extraction at the molecular level using α- and β-cyclodextrins

• Susana Santos Braga

Beilstein J. Org. Chem. 2025, 21, 1116–1125, doi:10.3762/bjoc.21.89

• to the thiol groups in the cyclodextrin. The authors further reported the process to be selective and to have good efficiency, with a gold removal yield as high as 96.1% in the presence of the thiolated β-CD derivative (Figure 5). Cyclodextrin recyclability was, however, not demonstrated and it is

Recent advances in synthetic approaches for bioactive cinnamic acid derivatives

• Betty A. Kustiana,
• Galuh Widiyarti and
• Teni Ernawati

Beilstein J. Org. Chem. 2025, 21, 1031–1086, doi:10.3762/bjoc.21.85

Biobased carbon dots as photoreductants – an investigation by using triarylsulfonium salts

• Valentina Benazzi,
• Arianna Bini,
• Ilaria Bertuol,
• Mariangela Novello,
• Federica Baldi,
• Matteo Hoch,
• Alvise Perosa and
• Stefano Protti

Beilstein J. Org. Chem. 2025, 21, 1024–1030, doi:10.3762/bjoc.21.84

• efficiency of the so obtained carbon nanomaterials was studied in the model photoreduction reaction of triarylsulfonium salts to diaryl sulfides. A comparison carried out on the results obtained points out the key role of the starting substrates in determining the photophysics and the photochemical

• efficiency of the resulting CDs. In this context, citric acid-derived materials (both graphitic and amorphous) were found as the most promising materials, while less satisfactory results have been observed when using CDs derived from glucose and biowastes. Keywords: agricultural waste; carbon dots (CDs

• nanomaterials synthesized from glucose, as well as those prepared starting from food wastes (bass scales and black berry residues from fruit preserves) resulted poorly efficient in the examined process. The obtained results also pointed out the efficiency of citric acid-derived CDs in the photoreduction of Ar3S

Recent total synthesis of natural products leveraging a strategy of enamide cyclization

• Chun-Yu Mi,
• Jia-Yuan Zhai and
• Xiao-Ming Zhang

Beilstein J. Org. Chem. 2025, 21, 999–1009, doi:10.3762/bjoc.21.81

• on this strategy, the authors also accomplished the total synthesis of (−)-lycospidine A in only 10 steps [20], another Lycopodium alkaloid with a truncated tetracyclic skeleton and distinct oxidation levels, further highlighting the versatility and efficiency of the enamide aza-Prins approach

• elegant [2 + 3] cycloaddition of secondary enecarbamates [28], the extension of this reaction to enamides lacking an N–H group is a notable advancement. After extensive optimization, the chiral dirhodium catalyst cat. 1 was found to be most capable in terms of both stereocontrol and efficiency. The use of